Raychaudhuri et al. reported amino acid polymorphisms at position 13 (or position 11 in strong linkage disequilibrium (LD) with position 13), 71, 74 of HLA-DRB1, position 9 of HLA-B, and position 9 of HLA-DPB1, which almost completely explain the MHC association to RA [11]. The gene discussed is HLA-DRB1; the disease is rheumatoid arthritis.